Adaptive resolution control scheme for RAKE receiver using delay profile conversion technique in DS/CDMA systems

This paper proposes an adaptive resolution control scheme for a RAKE receiver in direct sequence/code division multiple access (DS/CDMA) systems to effectively resolve and combine multipaths for high-bit-rate wireless multimedia services. In the proposed scheme, the receiver measures a delay profile for the received signal with its resolution equal to the highest chip rate, estimates delay profiles for lower chip rates using a delay profile conversion technique, and selects a chip rate that maximizes the received signal to noise plus interference power ratio (SNIR) under a condition that the number of RAKE fingers is limited by a certain number. Computer simulation confirms that the proposed scheme with a 3-finger RAKE receiver can reduce the average transmit power by about 5 dB without degrading the transmission quality under a 30-ray Rayleigh fading channel.